Walk into a forest, and most eyes go straight to the trees. Their trunks rise skyward, their crowns soak up sunlight, and their leaves store carbon. But the forest floor tells another story.
Mosses – those soft green mats underfoot – are proving to be far more than decoration. New research shows these overlooked plants deserve serious recognition in climate science.
A team led by Dr. Zhe Wang and Dr. Weikai Bao has conducted the largest survey of mosses in subtropical forests to date. They examined 413 forests across Sichuan Province, China, and measured the biomass of mosses and other understory plants.
The results surprised even seasoned ecologists. Mosses accounted for one-quarter of all understory biomass and about one percent of the aboveground tree biomass. That may sound like a small share, but across millions of hectares the effect is huge.
“For decades, mosses were treated as background scenery,” said Dr. Wang. “But our data shows they’re not just decoration – they’re critical carbon players hiding in plain sight.”
Mosses act as nutrient banks
The team didn’t stop at measuring plant mass. They analyzed carbon, nitrogen, and phosphorus stored inside mosses. The results revealed that mosses contribute around a quarter of nutrient storage in the understory.
Their green, photosynthetic parts push that share even higher. Because mosses recycle nutrients efficiently and decompose slowly, they act as long-term banks for forests.
That means less carbon released back into the air and more nutrients available when forests need them most.
Conifers provide moss stronghold
Cold, temperate coniferous forests turned out to be the stronghold. Shade, moisture, and stable ground create ideal growing conditions.
Conifer litter also causes fewer problems for mosses compared with broadleaf litter, which often smothers them. The study found moss present in most of these sites, while other forest types had far less coverage.
Natural and planted forests, however, showed little difference – highlighting how adaptable moss communities can be in different settings.
Global patterns emerge
Average moss biomass in the Sichuan forests measured about 65 grams per square meter, with some exceptional sites above 1,300 grams.
Compare that with boreal forests in Alaska, where moss carpets can weigh more than 12,000 grams per square meter.
In European spruce forests, dense moss mats also dominate the ground. Even tropical forests – though mostly covered with vascular understory plants – still hold large amounts of moss clinging to branches and trunks. These comparisons underline how widespread and varied moss contributions are worldwide.
Carbon science overlooks mosses
Most global carbon models ignore mosses altogether. Leaving them out creates a gap in how scientists understand natural carbon storage.
This research shows the omission is no longer defensible. By including moss biomass and nutrient storage, climate models become more accurate. Conservation programs can also recognize moss as a low-cost, high-impact ally in cutting emissions.
“Preserving bryophytes isn’t just about biodiversity,” said Dr. Bao. “It’s a cost-effective, nature-based solution for climate change. They’re like free carbon credits growing on the forest floor.”
Moss networks for climate insight
Though the study focused on subtropical China, its lessons are global. Mosses live in boreal, temperate, and tropical forests as well, each adding hidden carbon storage.
Large-scale surveys in these regions could expose just how much carbon is tied up in moss. Researchers believe global numbers may be even higher than what has been found so far.
“This is just the beginning. With collaborations like the China-Croatia Belt and Road Joint Laboratory, we’re building a global network to study overlooked ecosystems and their vital services,” said Dr. Wang.
Global collaboration fuels discovery
Next time you step into a forest, glance down. That thin green carpet may not stand tall, but it is working quietly to trap carbon, store nutrients, and stabilize the ground.
Forests are more than their trees, and moss proves that size does not always measure importance. The future of carbon neutrality may depend as much on the forest floor as on the canopy above.
This breakthrough was made possible through partnerships between institutions such as the Chinese Academy of Sciences, Shanghai Normal University, and the Shanghai Yangtze River Delta Urban Wetland Ecosystem National Field Observation and Research Station.
The study is published in the journal Carbon Research.
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